Phase formation of Mn-doped zinc silicate in water at high-temperatures and high-pressures

Luminescent silicate core–shell nanoparticles: Synthesis, functionalization, optical, and structural properties

“…The annealing temperature plays an important role not only in the aggregate formation during the particle preparation but also in the structural properties of the Mn 2+ -doped zinc orthosilicate [32,33]. In order to investigate the effect of the heat on the crystal- line phase formation of the nanoparticle shell, samples were annealed at different temperatures (800-1100°C) and analyzed by XRD.…”

Thermal analysis and mechanism of α-Zn2SiO4:Mn2+ formation from zinc oxalate dihydrate under hydrothermal conditions

“…The main route for a-Zn 2 SiO 4 formation in high-temperature water determined in this study is reaction (5). Zinc oxalate dihydrate is so stable in high-temperature water that it minimizes the progress of reactions (3) and (4) as discussed above.…”

“…In this study, hemimorphite, b-Zn 2 SiO 4 , and a-Zn 2 SiO 4 coexisted in water at 290 C. Zinc oxalate dihydrate coexisted with bZn 2 SiO 4 and a-Zn 2 SiO 4 in the range of 290e300 C where zinc oxalate anhydrate disappeared. Therefore, b-Zn 2 SiO 4 and a-Zn 2 SiO 4 most likely form from zinc oxalate dihydrate in high-temperature water according to reactions (4) and (5). Previous hydrothermal literature shows that the transformation of hemimorphite into a-Zn 2 SiO 4 proceeds via a direct route [31], reaction (7), rather than via reactions (6) and (8) going through b-Zn 2 SiO 4 .…”

“…Regardless of synthetic methods, starting materials affect growth rate that influences properties and morphologies of the final products. In previous work, we used zinc oxalate hydrate as a raw material for synthesizing a-Zn 2 SiO 4 :Mn 2þ in high-temperature and supercritical water [5]. At 400 C, zinc oxalate dihydrate formed almost completely a-Zn 2 SiO 4 for reaction times of 90 min shorter than from zinc oxide, hydroxide, and sulfate [6], and the reason for the differences still needs some type of quantification.…”

Rapid Production of Micro- and Nano-particles Using Supercritical Water

“…Photocatalytic activity of the PVA-assisted hydrothermally synthesized nanocrystalline SrTiO 3 powders for degradation of rhodamine B was much higher than those particles prepared without PVA [108]. [116][117][118] were synthesized in SCW in batch or flow reactors. Silver nanoparticles were produced by the thermal decomposition of Ag 2 O in SCW in a batch reactor for long reaction times (up to 60 min) [119].…”